Bioethanol water mix (e.g. overproof Rum or vodka e.g. Stroh 80) as an engine fuel?

I tried but it made my plane stand up on one leg then tip over....

| Have any tried to use a bioethanol water mix (e.g. overproof Rum or | vodka e.g. Stroh 80) as an (model) engine fuel?

Sounds expensive. And a waste! Unless the taxes are different over there -- here, if it's drinkable alcohol, it's heavily taxed and therefore much more expensive and regulated than something that's not drinkable.

| It might also be named 5D bioethanol?

Odd name. Why not just `ethanol' ? I guess bioethanol sounds more `green'.

| The engine should be made of corrosion resistant like materials | (e.g. ceramics):

Why? Our normal engines run on a mixture of methanol, oil and maybe some nitromethane. I don't doubt that ethanol and oil would work just as well, and a little water doesn't hurt things (but it's best to get it out when you store the engine, or it'll cause corrosion. After-run oil works pretty well.)

And the odd part is that all alcohol is "green", in the strictest sense. Methanol can be cooked from wood chips, leaves, grass, etc.

Ed Cregger

Hi Doug

I was trying to be a little ironic. Ok I should have written that. Sorry.

I did not write "5D".

Please read this document:

May 21, 2007, Moller international's rotapower engine achieves performance breakthrough using ethanol-water mix:

you can read, that the water cools the engine, reduces the emissions and reduced fire hazard.

-

Here you can read about: Super Ultra Low Emissions Vehicle:

/Glenn

I had an argument a few years ago with somebody on a car group about engine efficiency. I made the statement that half of your fuel is used for engine cooling through evaporation and expansion. The other person involved in that argument thought that was a ridiculous statement for some reason. Any Cessna pilot knows that fuel mixture controls head temperature.

Any piston engine can be made twice as efficient by making it out of high temp materials such as ceramics. Or you could inject water into the cylinder right after combustion, the water will expand and cool, and you can use normal materials. There was a guy in Australia a few years ago experimenting with water vapor injected into the manifold, with some success.

It seems to me that a water-alcohol mix would be an excellent idea, because you would get the cooling effect you want, plus the extra power when the water expands and pushes the piston, plus you could cut your use of the base fuel considerably. I just wonder if you would have to ignite it with a spark plug rather than a glow plug.

mix:

Vehicle:

I take everything from Moller with a block of salt. Their history is not good. We have run model airplane engines on ethenol and oil mixes as well as methenol/ethenol blends. This all to try and get around limits to fuel capacity in some racing events.. In an engine optimized for Methenol it works... but the fuel has fewer BTU's than either methenol or gasoline producing less power. Also alcohol/water injection is old news... WWII aircraft regularly used this to produce higher power at "wartime" throttle settings. It did not work in recipricating engines because of wear and tear on the engines... might work in a rotary/wakel type of engine like Moller uses. Also since model engines use oil mixed into the fuel too much water causes the oil to come out of suspension.... Bob Furr

Alcohol injection systems were used on radial piston engines at the height of piston engine development, just before jets came on the scene.

might

Couldn't you add a detergent?

Bioethanol is expensive even without the taxes. The inexpensive way to make ethanol is to make it directly from a hydrocarbon source such as - horror of horrors -crude oil. Run the crude through a cracker and then hydrate the ethylene. To my knowledge all the commercial ethanol used by industry is made from crude oil at considerably lower cost per gallon then bioethanol will ever be. When we run out of crude the cheap way will be from coal. An added advantage is such "chemically" manufactured alcohol is not loaded with all the fusal oils and crap that fermentation processes produce. Net result is much less hangover if you accidently drink it. You just need to be sure to QC the stuff to make sure it is not denatured. Generally you do find a tiny amount of methanol in it. But less methanol then you typically find in bioproduced drinking beverages like wine or any hard booze.

Ethanol works fine in a glo engine. You might need to twiddle the compression ratio a little. The carb setting will also be more critical. You will not get quite the power from a given displacement as you can not stuff as many BTUs worth of ethanol per cycle through the engine as you can methanol. For most purposes the power loss would not make any difference really. Models are typically over powered enough that a 15% power loss would not be a big deal unless you are hovering.

Hi Robert

I assume you mean this guy and this engine:

02/23/06 Inside Bruce Crower's Six-Stroke Engine: "..."I've been trying to think how to capture radiator losses for over 30 years," explains the veteran camshaft grinder and race engine builder..."It'll run for an hour and you can literally put your hand on it. It's warm, yeah, but it's not scorching hot...Indeed, the test unit has no external cooling system-no water jacket, no water pump, no radiator; nothing...Bottom-line, Bruce estimates his new operating cycle could improve a typical engine's fuel consumption by 40 percent. He also anticipates that exhaust emissions may be greatly reduced. It's all thanks to the steam..."

More about:

/Glenn

More about - Bruce Crower's Six-Stroke Engine:

Possible characterization: Steam machine powered and hybrid with an in situ ethanol powered engine?

/Glenn

If I remember reading correctly ethanol will not provide the necessary catalytic action to keep the glow plug lit, like methanol does. This would mean either spark ignition or continous glow plug heating with a battery to keep the engine running.

More like 75%. Very few IC engines achieve more than 25% thermal efficiency. I believe a best practice blown diesel at optimal throttle may do around 35%.

That however is for different reasons..weak mixtures burn faster and hotter.

No. The key is ultra high compression ratios by and large. And ultra lean mixtures. I.e. Diesel.

Or you could inject water into

Water injection allows slightly higher comp ratios without knocking, and the water becomes steam, and adds to the mass in the expansion volume.

You CAM do it but you ned up beyond a certain vlumke with ignition problems.

Ther most effivient heat engiones made are in power sttaions. One of the best aoppraoches has been to use a gas turbine, with the exhaust heating a boiler, and a steam condensing turbine on the back of it.

Heat engine efficiency is directly related to initial combustion temperature and final exhaust temperature. The higer the differential, the more power is extracted.

The problem with IC engines is that the kit to do this is heavy bulky and expensive, so not much use for an aero engine.

Water injection adds a few percent. sure, but its not a dramatic step.

My old MG midget was noticably faster on cold foggy days..maybe a single mph or two. But noticeable.

Well, that's the point, isn't it? Burning faster and hotter destroys the engine, so you richen the mixture to cool it off. The fuel is used as a coolant.

Sorry for the misunderstanding, but this appears to be one of those discussions where one person makes a true statement, and then another person claims that there are other more important factors even though that's not what the original conversation was about.

Considering airplanes in general, a lot of factors affect cylinder head temperature. Considering the function of fuel in a piston engine, at least half of the fuel is used for cooling. Use something else to cool the engine and you can avoid throwing the wasted fuel out the exhaust pipe. Then we could save the money we spend now on catalytic converters.

Uh, , I have yet to correctly identify a catalytic converter during any of my preflights. What brand airplane uses them?

Robert Reynolds wrote:

The original statement was that mixture controls cylinder head temp, and that is not true.... and neither is it true that half the fuel is used for cooling... (?) What gives you that idea? You're an engineer, right? you should easily understand this. In thermodynamic terms- The function of gasoline in an internal combustion engine is to provide a nearly instantaneous increase of temperature to the gases compressed in the cylinder, hence an increase in pressure in the cyl. With gas you also get about 26% more volume combustion product gasesthan you started with. Work is done as this pushes the piston down. The more heat the better. That heat is exactly what gives you power. [Glow engines generate much more volume of combustion product gases since they carry some of their own oxygen, and a lot less heat.] You want to avoid operation right at peak EGT because the ideal mixture (stochiometric) tends to erode the exhaust valve surfaces. Operation either on the lean or rich side of peak is okay, just not at peak EGT. Most people prefer to operate on the rich side since the power drops off much more gradually on this side. Incomplete combustion is another issue, and is usually due to either misfiring or an excessively rich mixture... Personally, I prefer to use the cooling system to cool the engine... yeah, it has its limits, like I said in my last post, but within these limits, it does a pretty good job; it also doesn't cost $5 a gallon. -Paul

Inlet charge cooling happens, which does cool the inflow to the cylinder. Adiabatic expansion also removes heat, and is roughly how that heat is converted to work. The rest goes out the exhaust, and may indeed add a few pounds of thrust as it does so.

I guess you can say that its the fuel air burn mixture that is responsible for cooling the thing, as thats what comes out hot. OTOH its the fuel air mixture that generates the heat too.

The difference is accounted for by the work produced, and the cooling system the engine employs.

Which probably just shows how dangerous a little knowledge is.